Numerical study of single impinging jets through a crossflow

This paper describes the application of three-dimensional finite-difference calculation procedures to the problem of a jet impinging on a flat plate through the influence of a confined crossflow. One procedure uses the hybrid central/upwind difference scheme, and the other uses a quadratic upstream weighted difference scheme (QUICK) to calculate the convection terms. The standard two-equation "& — c" turbulence model is used to calculate the distribution of the Reynolds stresses. The difficulty of assessing turbulence model performance in these complex flows due to the intrusion of numerical diffusion errors is demonstrated by comparing the calculations on both coarse and fine meshes and by improving the accuracy of the convection terms discretization using the higher-order QUICK method. The ability of the model calculations to simulate both the mean and the turbulence fields is examined, particularly in the vicinity of the stagnation point. The results show the advantages of QUICK differencing scheme over the hybrid treatment, since the same level of numerical accuracy requires far less CPU time and computer memory when the QUICK scheme is used. The calculations reveal the existence of large regions of low pressure, associated with an upstream recirculating flow region due to the interaction between the upstream wall jet and the crossflow, which may produce a substantial lift loss for a VSTOL aircraft.